Tracheoesophageal Fistula

Epidemiology

Tracheoesophageal (TE) fistula is a common congenital anomaly that occurs in one out of every 3,500 live births. TE fistula is commonly associated with other congenital malformations, particularly cardiac defects.

Esophageal atresia is a related congenital malformation with a presentation similar to that of a TE fistula and can occur with or without the presence of a fistula.

Pathophysiology

TE fistulas occur due to abnormal septation of the caudal foregut during the fourth and fifthweeks of embryonic development. Normally, the trachea forms as a diverticulum of the foregut and develops a complete septum that separates the esophagus from the trachea.

An abnormal posterior positioning of the tracheoesophageal septum will result in retained connection between the two compartments, resulting in fistula formation and atresia of the esophagus.

Isolated esophogeal atresia without TE fistula can occur when the esophagus fails to recanalize during week 8 of development.

Successive stages in the development of the tracheoesophageal septum during embryologic development. (A) The laryngotracheal diverticulum forms as a ventral outpouching from the caudal part of the primitive pharynx. (B) Longitudinal tracheoesophageal folds begin to fuse toward the midline to eventually form the tracheoesophageal septum. (C) The tracheoesophageal septum has completely formed. (D) If the tracheoesophageal septum deviates posteriorly, esophageal atresia with a tracheoesophageal fistula develops. From Dwayne et al, Am Fam Physician. 1999 Feb 15;59(4):910-916.

Several anatomic variations of TE fistula may occur. The most common type is the type C fistula which accounts for 84% of TE fistulas. The type C fistula includes proximal esophageal atresia with distal fistula formation. Polyhydramnios on fetal ultrasound is a common presentation of this type of fistula due to the inability of the fetus to swallow amniotic fluid. As a result, the proximal esophageal pouch may hypertrophy and cause compression of the trachea; this compression can cause additional complications including tracheomalacia.

The type E fistula is the most difficult to diagnose; it occurs without esophageal atresia and is sometimes referred to as an “H type” fistula due to its shape. The clinical presentation of an H type fistula is different than the other fistulae because it does not share the common presenting signs associated with atretic esophagus. Diagnosis of an H-type fistula can be significantly delayed because the only symptoms may be frequent episodes of pneumonia due to recurrent aspiration. The diagnosis of an H type fistula is made earlier if the fistula is larger as infants will present with choking during feeding due to large aspirations.

Types of TE Fistulas, from FreeEd Net & US Army

Associated Abnormalities

Additional congenital anomalies are commonly associated with esophageal atresia with and without TE fistulae and are present in 50% of infants presenting with the condition.

Of note, 25% of infants with esophageal atresia and TE fistulae have associated cardiac defects. The most common cardiac defects are ventricular septal defect, patent ductus arteriosus and tetralogy of Fallot. Imperforate anus, duodenal atresia, and malrotation are the most common gastrointestinal malformations. Musculoskeletal defects of the ribs and vertebrae are common. Renal and urologic defects such as hypospadias, renal agenesis, ureteral malformations, and horseshoe kidneys are commonly associated with esophageal atresia/TEF.

Multiple genetic abnormalities and syndromes are also associated with the development of esophageal atresia/TEF. Trisomies 13, 18, and 21 are commonly associated with EA/TEF. 10% of infants with CHARGE syndrome (an autosomal dominant syndrome associated with coloboma, heart anomaly, choanal atresia, mental retardation, genital hypoplasia, and ear abnormalities) also have concurrent EA/TEF.

Presenting Signs and Symptoms

Esophageal atresia/TE fistula may be suspected prenatally with ultrasound findings of polyhydramnios, absence of fluid in the stomach, small sized abdomen, or the presence of a dilated proximal esophageal pouch. Fetal MRI is the confirmatory test of choice prenatally.

Infants born with congenital esophageal atresia/TE fistula present with coughing, gagging, cyanosis, vomiting, voluminous oral secretions, and possibly respiratory distress. Abdominal distension may result if there is a fistula present between the trachea and distal esophagus.

If EA/TEF is suspected an attempt should be made to pass a radiopaque NG tube into the stomach of the newborn. In the presence of atresia no more than 10-12 cm will be passed before resistance is met; in the absence of atresia the stomach will be reached once 17 cm are passed.

Chest radiographs should be obtained following the attempted NG tube placement. Radiographic signs of EA/TEF are failure to pass an NG tube with coiling of the NG tube in the proximal atretic segment, tracheal compression, and absence of gastric bubble in pure esophageal atresia or with proximal fistulae. Barium swallow is infrequently needed and should be avoided but can be used to confirm the presence of EA/TEF if the diagnosis is in question.

Treatment

Initial treatment of EA/TEF should involve stabilization of the infant prior to transfer to a tertiary care center with pediatric surgery and intensive care services. The first action that should be taken is initiation of aspiration precautions by placement of a sump tube for suctioning of the pouch with elevation of the infants head.

IV fluids should be initiated and endotracheal intubation should be performed if there is any indication of respiratory distress. Bag mask ventilation should not be performed as it may cause gastric distension with distal esophageal fistula types.

Empiric antibiotic therapy for pulmonary prophylaxis (ampicillin gentamicin) is recommended by many experts due to the high risk of pulmonary aspiration.

Once transfer is complete the infant should be evaluated thoroughly for other surgically correctible associated congenital malformations prior to surgical repair of the EA/TEF. These evaluations include a thorough physical exam along with radiographic abdominal series, echocardiogram, and renal ultrasound.

If surgical repair needs to be delayed due to infection or the presence of additional congenital anomalies the infant should be supported with parenteral nutrition, gastrostomy tube placement, and continued upper esophageal sump suctioning until the time of repair.

Long term outcomes and complications

Long term outcomes with surgical treatment are highly favorable with survival near 100% for infants who are candidates for early surgical repair. In infants who require delayed treatment with parenteral nutrition until surgery can be undertaken survival ranges from 80-95% depending on the circumstance; conditions necessitating delay in treatment include pneumonia, low birth weight, premature birth, and additional significant congenital malformations that require delay of surgical therapy for correction. Congenital cardiac defects are the most frequent cause of death.

Most infants have esophageal dysmotility following repair and require referral to a speech and swallow speciality for additional management. Stricture formation is common and can be treated with dilation. Fistula recurrence occurs infrequently but necessitates additional surgery.

50% of EA/TEF patients will eventually suffer from gastroesophageal reflux disease. Half of those with GERD respond to pharmacotherapy, the other half require additional surgical intervention with fundoplication to prevent long term complications such as Barrett’s esophagus and adenocarcinoma.